The second step in the Realms of Truth.
To truly grasp the realm, one has to perfectly integrate Combat Techniques with every action.[1]
The only thing that is said is that experts who had reached this stage were rare even in Primordial City, and that one could not simply reach this realm by understanding its philosophy. They would need to temper themselves in countless life-or-death battles to execute the proper physical response.[1]
At that stage, experts could exhibit the power of Advanced Combate Techniques with their every move.